li $s0, 0 #row index
    li $s1, 0 #col index
    li $t2, '.'
    la $t1, grid
    li $t3, 40 #number columns //also the size of a row
    li $t4, 20 #number of rows
    mul $s2, $t3, 1 #rowsize = #cols * charsize
clearLoop1:
    beq $s0, $t4, endClear #if row index >= 20, break
    li $s1, 0 #column index = 0
clearLoop2:
    beq $s1, $t3, endClear2 #if column index >= 40, break
    mul $t5, $s0, $t3 #t0 = row index * rowsize
    add $t5, $t5, $s1 #offset = (t5 + s1)(rowValue*40+ColValue)
    sw  $t2, grid($t5) #save '.' into grid($t5), where $t5 is current offset
    addi $s1, $s1, 1 #col ++
    j clearLoop2
endClear2:
    addi $s0, $s0, 1 #row ++
    j clearLoop1
endClear1: